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Year 9 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers

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Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Quadratics

Year 9 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers

Factorise, then use the null factor law.

1.Solve: x2 − 15x + 54 = 0

Answer: x = 6 or x = 9

  1. Factorise: (x − 6)(x − 9) = 0
  2. Null factor law: x − 6 = 0 or x − 9 = 0
  3. x = 6 or x = 9
2.Solve: x2 − 5x + 4 = 0

Answer: x = 1 or x = 4

  1. Factorise: (x − 1)(x − 4) = 0
  2. Null factor law: x − 1 = 0 or x − 4 = 0
  3. x = 1 or x = 4
3.Solve: x2 + 4x + 3 = 0

Answer: x = −3 or x = −1

  1. Factorise: (x + 3)(x + 1) = 0
  2. Null factor law: x + 3 = 0 or x + 1 = 0
  3. x = −3 or x = −1
4.Solve: x2 − 7x − 18 = 0

Answer: x = −2 or x = 9

  1. Factorise: (x + 2)(x − 9) = 0
  2. Null factor law: x + 2 = 0 or x − 9 = 0
  3. x = −2 or x = 9
5.Solve: x2 − 18x + 81 = 0

Answer: x = 9 or x = 9

  1. Factorise: (x − 9)(x − 9) = 0
  2. Null factor law: x − 9 = 0 or x − 9 = 0
  3. x = 9 or x = 9
6.Solve: x2 + 15x + 54 = 0

Answer: x = −9 or x = −6

  1. Factorise: (x + 9)(x + 6) = 0
  2. Null factor law: x + 9 = 0 or x + 6 = 0
  3. x = −9 or x = −6
7.Solve: x2 − 4x − 21 = 0

Answer: x = −3 or x = 7

  1. Factorise: (x + 3)(x − 7) = 0
  2. Null factor law: x + 3 = 0 or x − 7 = 0
  3. x = −3 or x = 7
8.Solve: x2 + 11x + 28 = 0

Answer: x = −7 or x = −4

  1. Factorise: (x + 7)(x + 4) = 0
  2. Null factor law: x + 7 = 0 or x + 4 = 0
  3. x = −7 or x = −4
9.Solve: x2 + 2x − 24 = 0

Answer: x = 4 or x = −6

  1. Factorise: (x − 4)(x + 6) = 0
  2. Null factor law: x − 4 = 0 or x + 6 = 0
  3. x = 4 or x = −6
10.Solve: x2 + 10x + 24 = 0

Answer: x = −6 or x = −4

  1. Factorise: (x + 6)(x + 4) = 0
  2. Null factor law: x + 6 = 0 or x + 4 = 0
  3. x = −6 or x = −4
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